Fuel injection for internalcombustion engines



J. E. TILLIET FUEL INJECTION FOR INTERNALCOMBUSTION ENGINES Filed July 24, 194e ATTORNEYS -INVENTOR JEAN EMILE TILLIET E] gg A Patented Apr. ll, 1,950

' UNITED STATES PATENT OFFICE FUEL INJECTION FOR INTERNAL- COMBUSTION ENGINES Jean Emile Timer, Neuilly-sur-seine, France Application July 24, 194s, sei-ni N0. 685,881 In France July 23, 1945 9 claims; (ci. 12a-65) It is already known, for engines of large cylin-` der capacity and.running at low speed, to feed them with'a very lean air and fuel mixture permitting very high compressions without selfignition or spontaneous explosion and to promote ignition at the desired time by injecting into the cylinders a, certain amount of liquid fuel, in particular oil, when the piston is close to the end of its compression stroke.

There is no essential diillculty in measuring and delivering the amount of loil that produces, through its injection, ignition of the compressed mixture, since the amounts of fuel to be injected for each cylinder are relatively high.

However, this is not the case with engines running at high speed and/or having a greatnumber of cylinders each of low capacity. In order to operate such engines as above indicated, the amounts of liquid fuel to be injected to produce ignition of the highly compressed lean mixture become so small thattheir delivery by means of a pump is extremely difficult, if not impossible.

The object of my invention is to obviate this difficulty.

With this object in view, according to an essential feature of my invention, in order to promote ignition of the lean airand fuel mixture highly compressed in the engine cylinder during the compression stroke, I inject a very rich air and fuel mixture into this lean mixture near the end of said stroke, the richnessv of the mixture that is injected being such that there is no possibility of spontaneous ignition thereof when it is subjected to the injection pressure, whereas its volume per cycle and pe'r cylinder unit is sufflcient for making it possible to deliver it by means of a pump. Preferably, care is taken of obtaining in the engine cylinder, after injection of the too rich mixture and its incorporation into the too lean mixture, a final mixture of the de- In the example shown by the drawing, the invention is applied to a two stroke engine having its cylinders in line, which may be of any suit- .able construction.

For instance it includes a frame I, carrying cylinders 2 in each of which there is a piston 3 connected by a rod 4 with a crank arm 5 of rotary oscillating motion about the cylinder. axis to control the air intake ports 8 `and the exhaust ports 9 provided in the wall of cylinder 2. I provide said sleeve, at the level of the intake ports 8, with a large packing ring I0 fixed thereto in such manner as to participate in its rotary movement and provided with ports located opposite corresponding ports of the sleeve valve for ensuring the control of admission to the cylinder as it will be hereinafter explained.

In-order to give sleeve 'I the desired oscillating rotary movement, shaft 6 is made to drive, through an auxiliary shaft II provided with two helical pinions I2, a disc I3 journalled in the engine frame. This disc I3 carries a crank arm I4 which, through 4the intermediate of a link IB, drives sleeve 1, the movement of this link in two planes respectively perpendicular to each other being made possible by the provision of rings Il. I1A respectively journalled on crank I4 and on a bearing I8 rigid with said sleeve valve.

In such an engine, at the end of the combustion or ldownward stroke, piston 3 uncovers the exhaust port, then cleared by sleeve l. The combustion gases escape. Immediately after this, sleeve 1 establishes communication between cylinder 2 and inlet port 8, fed with compressed air from any suitable source (not shown). Scavenging then takes place and when, upon the upward stroke of piston 3, port 9 is closed the cylinder is full of fresh compressed a'ir.

The feed of fuel to the cylinder takes place in two steps; a first portion, corresponding forinstance to about 40% of the total amount of fuel supplied vper cycle, is advantageously introduced at the beginning of the compression stroke, after ,exhaust port 9 has been closed, into cylinder 2 through conduit I9. This conduit opens into saidv cylinder `through a port controlled by sleeve I, and preferably located opposite a hot part such as the head 20 of cylinder 2, advantageouslyprovided with an inclined recess 2i intended to deilect andto diffuse the jet of fuel in said cylinder. This first portion of the fuel constitutes with the air previously admitted through port 8 a lean mixture including lfor instance about 1 3 per cent in volume of gasoline, which does not risk spontaneous ignition, despite the high rate of compression, for instance 12 to 1, to which it issubjected.

A second portion of fuel corresponding, for instance,'to about 60% of the whole amount of fuel admitted into cylinder 2 per cycle of the engine, is injected, after it has been mixed with air, through an aperture 22 also controlled by sleeve 1, for entering into contact with the highly compressed and hot lean mixture. This injection, which takes place when piston 3 is close to the end of its inward stroke, causes ignition to take place. The mixture that contains this second portion of the fuel is made very rich (for` instance 17% in volume of gasoline), sufficiently so for preventing spontaneous ignition thereof before its injection into cylinder 2 despite the high pressures to which this mixture is subjected in the pump through which it is injected.

It should be noted that the percentage values above indicated are given merely by way of indication and cannot, in any way, be considered as limiting the scope of my invention. `They depend, of course, essentially upon the characteristics, and in particular the octane number, of the fuel that is utilized.

The fuel injection pump may be of any suitable construction. However, according to a preferred embodiment, it includes, along each cylinder 2, an auxiliary cylinder 23 parallel thereto and cooperating with a slide valve 24-25 cooperating with a fixed piston 26. Elements 24--25, on the one hand, and 26, on the other hand, are

adapted to ensure fluidtightnes/s about inlet ports -2`| and 23 provided for air and fuel respectively and exhaust port 29 provided for the delivery of the rich mixture that is formed and placed under pressure, during the upward stroke of the pump piston, inside portion of the slide valve. Delivery of the rich mixture and its injection into cylinder 2 take place when port 29 is located opposite port 22 which, at this time, is cleared by an aperture provided in sleeve 'I.

In order to drive the rich mixture injection pump, I preferably make use of the same rotary disc I3 which serves to impart an oscillating rotary motion to sleeve 'I, by providing this disc with a second crank 30 connected, through a link 3|, with the pump slide valve 24, 25.

By way of indication having no limitative arcane 487,759, filed February 7, 1944, for Improvements brought to feed systems for internal combustion engines.

' accurate feed control however small the amount of fuel to be fed may be. It includes a fixed tube 32 provided with holes 33, 34 one for the rich mixture and the other forthe lean mixture, the inside of this tube 32 being connected with' the delivery of a pump, preferably a volumetric pump (not shown on the drawing) the flow rate of which is .proportional to the number of revolutions of the engine. Around this tube 32 is mounted a concentric sleeve 35 having, opposite holes 33and 34, corresponding holes 36, 31, whereby it is possible, by operating a lever 38 rigid with said sleeve, to vary the flow section through said holes. Tube 32, with its sleeve 35, is mounted inside a rotating cylindrical valve 33 open at one end and the inner diameter of which is greater than the outer diameter of sleeve 35 so that an annular space is left between valve 39 and sleeve 35, two radial nozzles 40, 4I, carried by the inner wall of valve 39, respectively in the radial planes of holes 33 and 34, projecting into this interval. Said valve 39 is mounted in a ilxed casing 42 the wall of which is provided, in radial planes corresponding to holes 33, 34 and nozzles 40, 4|, with ports 43, 44 which communicate respectively on the one hand with a conduit 45 leading to the rich mixture injection pump when the aperture 28 of slide valve 25 is opposite this conduit, and on the other hand with conduit I9,

through which the fuelserving to the formacharacter, it is to be noted that, for a cylinder capacity of 100cm.8 of cylinder 2, the injection pump may be given a cylinder capacity of 8 cm.

If the air and fuel mixtures have the composi' tion above indicated, the following result is tained:

a. the lean mixture that is compressed in cylinder 2 contains 1 cm.s of gasoline vapor at 75 C. under a pressure of '160 mm. of mercury, i. e. about 3.5 mg. of gasoline;

b. the rich mixture that lis injected by the pump contains 1.4 om.3 of gasoline vapor at C. under a pressure of '160 mm. of mercury, i. e. about 5 mg. of gasoline;

c. the final mixture obtained by the mixing together of the two initial mixtures contains about 2.2% in volume of gasoline vapor at 75 C. under a pressure of 76,0 mm. of mercury, this number constituting an optimum value.

Whereas the two initial mixtures a and b are not inflammable at the temperatures resulting from the compressions applied thereto, the iinal mixture c that is obtained will ignite spontaneously.

tion of the lean mixture is fed to cylinder 2.

Valve 39 is provided at one of its ends with a helical wheel 45 driven through the intermediate of wheels 4`I, 48 mounted on a shaft 49, from the shaft that carries crank plate I3.

At the desired times, that is to say when nozzles 40, 4I are located opposite their corresponding holes 33, 34, rotating valve 39 allows predetermined amounts of fuel to flow from the inside of tube 32 into conduits 45 and I9 from which they reach cylinder 2 and the rich mixture injection pump respectively. During the periods for which ports 43, 44 are closed by valve 39, the fuel delivered by the pump fiows back to a point located on the upstream side of this pump and escapes through the open end of cylindrical element 39.

As the flow rate of the jet is proportional to the speed of revolution of the engine and the time for which nozzles 49, 4| pass in front of holes 33, 34 is inversely proportional to said speed, the inflow of fuel per cycle is constant as long as adjustment sleeve 35 is kept in fixed position with respect to tube 32. l f

Inorder to adjust the amounts of air serving respectively to the formation of the rich mixture and to that of the lean mixture, advantageously, I combine, by means of suitable link means, the movement of sleeve 35 with the movements of the two control members (throttles, needle valves etc.) 5I, 52, respectively disposed in the air intakes leading to cylinder 2 and to injection pump 23-24-25.

Such an internal combustion has, in particular, among other advantages, the following ones:

1. Possibility of ensuring, in an engine having a high speed of revolutions and a small unitary Such a device permits a very I asoaeu 'I of fuel, which are very small forall working-conditions.

In a general manner, while I have, in the above description, disclosed what I deemto be practical and efllcient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changesmade in the arrangement, disposition and form of the parts without` departing from the principlev of the present invention as comprehended within the scope of the accompanying claims.

, What I claim is: v l

l. An internal combustion engine which comprises, in combination, a cylinder, a piston in said cylinder, means including a sleeve valve in said cylinder operatively connected with said piston for feeding into said cylinder, during the compression stroke of said piston, air and fuel in proportions to form a, lean lmixture non liable to ignite spontaneously under the effect of compression by the piston, said cylinder and .said sleeve valve being provided with respective ports adapted to register together near the end of said compression stroke to form a supplementary inlet to said cylinder, and means including an injection pump for feeding said supplementary inlet with an air and fuel mixture sufficiently rich to pre- .vent spontaneous ignition thereof under the effect of the injection pressure of said pump.

2. An internal combustion engine which comprises, in combination, a, cylinder having an air inlet port, a fuel inlet port and a supplementary air and fuel mixture inlet port, a piston in said cylinder, means including sleeve valve in said cylinder operatively connected with vsaid piston for temporarily opening said air and fuel inlet ports at the beginning of the compression stroke of said piston, and said supplementary inlet port near the end of said compression stroke, means for feeding to the first mentioned inlet ports air and fuel respectively in proportions corresponding to a mixture sumciently lean to prevent spontaneous ignition thereof under the effect of the compression stroke, and means including an injection pump for feeding said supplementary inlet port with an air and fuel mixture sufliciently rich to prevent spontaneous ignition thereof under the v effect of the ignition pressure of said pump.

3. An internal combustion engine which comprises, in combination, a cylinder having an air inlet port in communication with the atmosphere, a fuel inlet port and a supplementary air and fuel mixture inlet port, a piston in said cylinder, means operatively connected with said piston for temporarily opening said air and fuel inlet ports at the-beginning of the compression stroke of the piston, an injection pump having its delivery conv sion stroke and with the air admitted through `said pump inlet a mixture suillciently rich to prevent spontaneous ignition thereof under the effect of the ignition pressure of Isaid pump.

4. An internal combustion engine which comprises, in combination, a cylinder having an air inlet port in communication with the atmosphere, a fuel inlet port and a supplementary air and fuel mixture inlet port, a piston in said cylinder, means including a sleeve valve in said cylinder operatively connected with said piston for temporarily opening said air and fuel inlet ports at the beginning of the compression stroke of the piston, an injection pump having its delivery connected with said supplementary inlet port, said pump having a fuel inlet and an air inlet intermittently in communication with the atmosphere, and means .for alternately feeding fuel to the fuel inlet of tion thereof under the effect of the compression stroke and with the air admitted through said pump inlet a mixture sufficiently rich to prevent spontaneous ignition thereof under the effect of the ignition pressure of said pump.

5. An internal combustion engine which comprises, in combination, a cylinder having an air inlet port in communication with the atmosphere, a fuel inlet port and a supplementary air and fuel mixture inlet port, a piston in said cylinder, means operatively connected with said piston for temporarily opening said air and fuel inlet ports at the beginning of the compression stroke of the piston, an injection pump having its delivery connected with said supplementary inlet port, said pump having a fuel inlet'and an air inlet lntermittently in communication with the atmosphere, and means including a rotating vahe driven in synchronlsm with said piston to control an endless flow of fuel for alternately feeding fuel to the fuel inlet of said cylinder and the fuel inlet of said pump respectively at a rate such as to form with thev air admitted through said cylinder air inlet a mixture suiflcientlylean to admitted through said pump inlet a mixture sufficiently rich to prevent spontaneous ignition thereof under the eiect of the ignition pressure of said pump.

6. In an internal combustion engine, the combination of a cylinder, a piston in said cylinder, means operatively connected with said piston for feeding into said cylinder at the beginning of the piston compression stroke a fluid mass uninfiammable under the effect of compression in said cylinder, said fluid mass being constituted at least partly by air, means for forming and kcompressing an air and liquid fuel mixture to a pressure higher than that existing in said cylinder at the end of the compression stroke, said air and fuel mixture being sufficiently rich to prevent spontaneous ignition thereof under the effect of said pressure, and means operatively connected with said piston for injecting the air and gasied fuelfmixture from said compression means into said cylinder at the end of the compression stroke, the relative amount and composition of this mixture being such as to form, by admixture with the fluid mass already present in the cylinder, a final mixture which ignites spontaneously under .the pressure and temperature conditions existing at this time in said cylinder 7. In an internal combustion engine, the combination of a cylinder. a piston in said cylinder, means operatively connected with said piston for feeding into said cylinder, at the beginning of the taneous ignition thereof under the en'ect of compression in said cylinder, means for forming and compressing an air and liquid fuel mixture to a pressure higher than that existing in said cylinder at the end of the compression stroke, said last mentioned mixture being sufficiently rich to prevent spontaneous ignition thereof under the effect of said pressure, and means operatively connected with said piston for injecting the air and gasified fuel mixture from said compression means into said cylinder at the end of the compression stroke, the relative amount and composition of this last mentioned mixture being such as to form, by admixture with the mixture already present in said cylinder, a final mixture which ignites spontaneously under the pressure and temperature conditions existing at this time in said cylinder. f

8. In an internal combustion engine, the combination of a cylinder, a piston in said cylinder, means operatively connected with said piston for feeding into said cylinder at the beginning of the piston compression 4stroke a fluid mass uninflammable under the effect of comn compression stroke, air and fuel in proportions to form a suiliciently lean mixture to prevent sponthe' pressure and temperature conditions existing at this time in said cylinder.

. 9. In an internal. combustion engine. the combination of a cylinder, a piston in said cylinder, means operatively connected with said piston for feeding into said cylinder, at the beginning of the compression stroke, air and fuel in proportions to form a sufficiently lean mixture to prevent spontaneous ignition thereof under the eilect of compression in said cylinder, means including a volumetric pump operatively connected with said piston for forming and compressing an air and liquid fuel mixture to a presser higher than that existing in said cylinder at the end of the compression stroke, `said last mentioned mixture being sumciently rich to prevent spontaneous ignition thereof under the effect of said pressure, and means operatively connected with said piston for injecting the air and gasified fuel mixture from said pump into said cylinder at the end of the compression stroke, the relative amount and composition of this last mentioned mitxure being such'as to form. by admixture with the mixture already present in said cylindera final mixture pression in said cylinder, said fluid mass being constituted at least partly by air, means including a volumetric pump operatively`connected with said piston for forming and compressing an air and liquid fuel mixture to a pressure higher than that existing in said cylinder at the end of the compression stroke, said air and fuel mixture being sumciently rich to prevent which ignites spontaneously under the pressure and temperature conditions existing at this time in said cylinder.

' JEAN EMILE 'I'ILIrIE'IZ REFERENCES CITED The following references areof record the file of this patent:

UNITED STATES PATENTS -2,236,742 Allyn Apr. 1, 1941 

